Deckle edge cutting knife



May 5, 1970 H. HQPPE 3,509,790

DECKLE EDGE CUTTING KNIFE Filed 001:. 16, 1968 2 Sheets-Sheet 1 FIGI H02 I! I I nliii h L r g rklmhnh INVENTOR HORST HOPPE ATTORNEY May 5, 1970 H. HOPPE 3,509,790

DECKLE EDGE CUTTING KNIFE Filed Oct. 16, 1968 2 Sheets-Sheet 3 INVENTOR HORST HOPPE ATTORNEY United States Patent T DECKLE EDGE CUTTING KNIFE Horst Hoppe, 25 Ulmenstr., 3012 Langenhagen- Friedenau, Germany Filed Oct. 16, 1968, Ser. No. 768,082 Claims priority, application Germany, Oct. 19, 1967, 1,536,462 Int. Cl. B26d 1/06, 3/14 US. Cl. 83-697 7 Claims ABSTRACT OF THE DISCLOSURE The deckle edge cutting knife is usable in a double shear or swing cut type paper cutting machine and has profile and complementary sharpening or serrated grooves on opposite sides of the knife. The serrated edge forms an angle with the cutting edge of the knife up to 30 degrees greater than the angle that the grooved profile side forms with the cutting edge of the knife. The backside of the knife is tapered such that when the knife is fastened in the knife holding bar, the profile edge inclines away from the paper stack.

The present invention relates to cutting knives for sheet material cutting machines and particularly relates to a profile knife blade for cutting deckle edges and usable with cutting machines of the double shear cut type.

Previously, sheet material, i.e., paper, cutting machines, comprised two general types, the vertical cut and shear cut. In the vertical cut type, the knife blade is disposed such that its cutting edges lies horizontal with respect to the plane of the paper in the paper stack to be cut. This knife blade moves vertically through the paper stack, cutting successively through each individual piece of paper. In the shear type paper cutting machine, the knife blade is disposed such that its cutting edge extends horizontally with respect to the paper being cut. The knife blades moves diagonally through the paper with the individual paper sheets being cut through in succession. As is obvious, these two types of cutting machines require a large downward force to be applied to the knife blade since only a smooth or straight cut is made through each piece of material in succession. This limits the capacity of machines of these types.

The present trend in the paper cutting industry is to employ paper cutting machines commonly known as the double shear cut type or which provide a so-called Swing cut. In this type of machine, the knife blade is disposed such that its cutting edge initially forms an acute angle with the stacked sheet material. The motion of the blade in the course of the cut is a combined pivoting action coupled with a diagonal movement. With this type of cutting course, the individual sheets of material are cut through at different points therealong starting at one edge of the stacked material and cutting through to its opposite edge, depending upon the position of the knife blade rather than cutting through each piece of material in succession as in the vertical or shear type cutting machines. The cut provided in the double shear cut type machine essentially starts at one edge of the stacked material and traverses the stacked material toward its opposite edge with a plurality of the sheets thereof being cut partially through simultaneously. This double shear cutting action thus reduces the energy expenditure of the cutting machine and provides for greatly improved capacity of the machine. A characteristic of the double cut is that a different swing curve develops at each point along the knifes edge during its movement between its initial and lower cut through positions. This, of course, is the key to the success of this double shear cut type machine when employed in conjunction with a smooth cutting knife but this provides 3,509,790 Patented May 5, 1970 significant disadvantages when a profile is formed in the knife blade in order to cut deckle edges.

Deckle edge cuts have heretofore been provided in the vertical type cutting machines by providing vertically grooved profile edges. However, where the vertical type cutting machines are not employed, the trend being away from such machines, and where a double shear cut type machine is employed, a separate cutting operation is required in order to provide a deckle edge. In other words, the stacked sheet material is first cut by means of a smooth or straight cutting knife edge provided in the double shear cut type machine to dimensions slightly oversized than that desired with a second cutting operation, e.g., a die cutting operation, being necessary to form deckle-edged patterns about the edges of the material. This, of course, is a time consuming, laborious, and expensive additional operation which is completely eliminated by use of the deckle edge knife blade of the present invention, as will hereinafter become clear. Where a profile is formed in the backside of the knife in vertical cut type machines to form deckle-edged cuts, the profiles in the cut material and in the backside of the knife complement one another throughout the full range of movement of the knife blade. Since a different swing curve develops at each point along the edge of the knife during its combined pivoting and diagonal movement characteristic of a double cut type machine, it will be seen that the employment of such previously known deckle edge cutting knife blades in a machine of the double shear cut type provides a profile in the material and in the backside of the knife displaced, one from the other, from point to point, throughout the course of the cut. This results in a buckling of the material and an increase in the energy requirements of the machine due to the interference caused by the cut material with the flanks of the profile side of the blade. A like result occurs on the sharpened side of the knife blade.

In the case of vertical and shear cuts, each individual layer of the stack is cut through separately whereas in the double shear cut machine, the individual layers of the material are cut through differently and from one edge to the opposite edge at different points in time during the course of the cut. Whereas, in the former type machines, the cut material was able to escape unimpeded, the cut material in a double shear cut type machine cannot escape as it has not been cut through. Thus, these layers of partially cut material exert a steadily increasing pressure along the knife blade as the knife cuts through the material. This results in a so-called undercut (the upper layer of material being wider than the lower layer).

Accordingly, it is a primary object of the present invention to provide a deckle edge cutting knife blade for cutting machines of the double shear cut type. To this end, the sharpening grooves or ground serrated edge of one side of the knife blade is formed at an angle with the cutting edge of the knife of up to 30 degrees greater than the angle formed between the profile grooves formed on the other side of the knife blade and the cutting edge of the knife. The difference between the angles of the backside profile grooves and the serrated edge groove is determined by the distinct curve of descent of the cutting machine in which the deckle edge blade is to be mounted. By providing greater angularity of the serrated edge grooves relative to the cutting edge, the profile flanks facing away from the curve of descent cannot be caught or jammed in the layers of material which have not as yet been entirely out through since these flanks are ground cut underlying sheets of material. To accomplish this, the outer face of the knife blade is tapered slightly such that when secured to the knife blade holder, the back profile grooves incline away from the cut edges of the material, i.e., the back profile side of the knife blade forms an acute angle with the cut edges with the cutting edge of the blade forming the apex of the angle. To provide further relief, the shank portion of the profile side of the knife blade is ground corresponding in depth to the profile grooves.

These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, claims, and appended drawings wherein:

FIGURE 1 is a diagrammatic illustration of a double shear cut type cutting machine in which a cutting blade constructed in accordance with the present invention is specifically adapted;

FIGURE 2 is a fragmentary plan view of a sheet of material illustrating the deckle edge cut by the knife blade of the present invention;

FIGURES 3 and 4 are enlarged fragmentary elevational views of opposite faces of the knife blade hereof;

FIGURE 5 is a view of the cutting edge of the knife taken about on line 55 of FIGURE 3;

FIGURE 6 is an enlarged end elevational view of the knife blade hereof;

FIGURE 7 is an enlarged fragmentary elevational view illustrating the cutting edge portion of the knife blade hereof; and

FIGURES 8 and 9 are schematic illustrations of respective opposite sides of the knife blade in the course of a cut through a stack of sheet material.

Referring now to the drawings, particularly to FIG- URE 1, there is schematically illustrated a sheet material cutting machine 10 of the double shear cut type and a stack of sheet material 12 underlying a knife blade 14 secured to a knife blade holder 16, the blade and holder therefor being illustrated in an initial raised position prior to cutting. As illustrated by the arrows above machine 10, the knife blade 14 and holder 16, by means of known mechanisms not shown and disposed in machine 10, ohtains a simultaneous downward pivoting and diagonal movement. The lowermost position of the knife after cutting through a stack of sheet material is illustrated by the dash lines and locates the cutting edge 18 of the knife in a position parallel to the sheet material supporting table portion 20 of machine 10.

The knife blade 14 of the present invention is specifically formed to provide a deckle edge cut along the stacked sheet material as it passes therethrough. As an example thereof, there is illustrated in FIGURE 2 a sheet of material having a deckle edge out as at 22 which may be provided by a blade formed in accordance with the present invention. Obviously, other deckle edge patterns can be provided as desired.

The knife .14 comprises an elongated knife blade having a shank portion 26 and a cutting edge portion 28. A plurality of openings 30 are formed through shank portion 26 at longitudinally spaced positions therealong and receive bolts 32 which fasten knife blade 14 to the knife holder 16. Referring now to FIGURE 4, the backside or profile side of the cutting edge portion 28 is provided with a plurality of diagonally extending grooves 34 which open through and terminate in a lower cutting edge 36. The grooves 34 are formed only along the lower portion of the backside of the knife blade and are preferably formed only along the lower one-third of the height of the knife blade. The remaining backside portion of knife blade 14 is ground in or relieved as indicated at 38 for reasons as will presently become clear and preferably to a depth corresponding to the depth of the profile grooves 34. The opposite side of the knife blade in the area of cutting edge portion 28 is tapered as at 39 toward the profile side of the blade to converge toward and form the cutting edge 36 with the profile grooves 34. A plurality of sharpening grooves or serrations 40 are formed adjacent the cutting edge 36 along the tapered edge portion 39 and are complementary to the profile grooves 34 along the cutting edge 36. In other words, where there is a recess on the profile side of the blade, there is a ridge formed on the serrated grooves 40. Note that this complementary formation provides a cutting edge which, as seen in elevation, forms a straight line. The shank portion 26 of the knife has a tapered relief indicated at'42 in FIGURE 6, which extends substantially from the tapered portion 39 of the blade 14 to its rear edge 44. Thus, when the knife blade 14 is mounted against the knife holder 16 with the tapered relieved face of shank portion 26 butting the vertical face of the knife holder 16, the profile side of the knife blade including profile grooves 34 and relieved shank portion 38 form a slight vertically opening, acute angle with the cut sides of the sheet material during the course of the cut for reasons as will become apparent.

It is a particular feature of the present invention that the angles which the profile grooves 34 and the serrated grooves 40 from which the blade cutting edge 36 are formed in a predetermined relation. Particularly, the serrated grooves 40 form an angle c with cutting edge 36 greater than the angle 1 formed by profile grooves 34 and cutting edge 36, such angle e being up to 30 degrees greater than the angle 1. The particular increase in the angle of the serrations 40 relative to the grooves 34 is determined and depends on the distinct curve of descent of the machine in which the knife blade will be employed. The curve of descent in each machine varies as its capacity, the length of the knife blade utilized and other factors and each blade hereof is ground or customized to the particular machine. As a specific example, it has been determined that for many machines a dilference of 15 degrees is satisfactory. Thus, for a profile groove angle 1, for example, of 43 degrees, the serrated groove angle e will be 58 degrees. By providing a steeper angle of serrated grooves 40 than the profile grooves 34 the profile flanks are no longer used as supports. In other words, the profile flanks facing away from the curve of descent cannot be caught and jammed in the layers of sheet material which have as yet not been entirely cut through since these flanks are ground out positively from the curve of descent of the blade. These angles are illustrated specifically in FIGURES 8 and 9 wherein the opposite sides of the blade are illustrated with reference to the stacked sheet material.

It is a further feature hereof that the profile side of the knife blade is inclined relative to the stacked material and forms a slight vertically opening acute angle with the cut edges of the sheet material during the course of the out. In this manner and when the knife blade passes through the sheet material, substantially only the portion of the profile grooves 34 adjacent the cutting edge 36 will cut or bear in the stacked sheet material with the remaining portions of the profile grooves 34 spaced back from cutting edge 36 being spaced inclined away from the cut edges of the material. To further insure that the following face portions on the profile side of the knife blade facing the stacked cut sheet material do not engage or otherwise interfere with the cut deckle edge portions of the sheet material, the profile side shank portion is ground out to form a relief as indicated at 38. Thus, as the knife passes through the sheet material, only a very small portion of the profile grooves 34 adjacent the cutting edge 36 engage and cut through the sheet ma terial with the remaining portions of the entire profile side of the knife angling away from the cut sheet material.

As a specific illustrative example of the knife blade hereof, the grooves 34 form an angle of 43 degrees with the cutting edge 36 while the grooves 40 on the opposite face of the knife form an angle of 58 degrees with the cutting edge 36. The grooves 40 form an angle with the cutting edge 36 up to 30 degrees greater than the angle that the grooves 34 form with cutting edge 36. The tapered edge portion 39 of the knife blade forms an angle 0 preferably between 10 and 30 degrees with the profile edge in order to make the cutting edge 36 as thin as possible and in order to guarantee a proper slippage of the cut material as the knife passes therethrough. The cutting angle indicated at d lies preferably between 15 and 40 degrees and depends on the material that is to be cut. As a further advantage hereof, it will be noted that knives of known design which have been provided for the vertical and diagonal cut can be readily and without waste transformed to the shape of the present knife blade such that they may be usable to form a deckle edge knife blade usable in the double cut type cutting machines.

Thus, the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is: p

1. A knife for use in cutting deckle edges on stacked sheet material and employed with cutting machines of the double shear cut type comprising an elongated knife blade having a shank portion and a cutting portion along a long edge of said blade, said cutting edge portion having a tapered side and a plurality of profile grooves formed along the opposite side thereof, the axes of said grooves forming an acute angle with the cutting edge of said blade, the tapered side of said cutting edge portion having a plurality of serrations formed therein and forming an angle with the cutting edge of said blade greater than said acute angle, said serrations being complementary to said grooves along the cutting edge of said blade.

2. A knife according to claim 1 wherein a face portion along one of said sides of the knife blade and spaced back from the long edge of said blade is relieved.

3. A knife according to claim 1 wherein a face portion of the knife blade spaced back from the long edge thereof and on the side of said blade carrying said serrations is inwardly tapered to converge toward the rear edge of the shank portion of the blade opposite its cutting edge.

4. A knife according to claim 1 including means in cluding a vertically extending face portion for mounting the knife blade along a side face portion thereof, said side face portion being inwardly tapered such that the knife blade is mounted in a canted position with the vertically extending and side face portions engaging one another whereby the face of the cutting portion containing the pro-file grooves is inclined relative to the stack of cut sheet material.

5. A knife according to claim 3 wherein a face portion of the knife blade face spaced back from the long edge thereof and on the side of the blade carrying the profile grooves is relieved.

6. A knife according to claim 1 wherein the dilference in the angle formed between the respective profile grooves and the cutting edge and the serrations and the cutting edge is less than 30 degrees.

7. A knife according to claim 1 wherein the acute angle formed by said grooves develops as an intermediate value between the setting angles of the knife blade in the cutting machine.

References Cited UNITED STATES PATENTS 2,325,634 8/1943 Rod 83-918 X 3,277,764 10/1966 Henc 83-697 X 3,340,758 9/1967 Peterson et al 83-697 FRANK T. YOST, Primary Examiner US. Cl. X.R. 83-918 

